This invention relates generally to electromagnets. More specifically, it relates to an electromagnetic positioning device capable of provide an output force essentially linear with respect to the applied current.
Electromagnetic acutators or positioners are of course well known in the art and are in common use. One such device is shown in the patent to Barrett et al. No. U.S. Pat. No. 3,883,839, wherein the actuator or armature moves on a shaft and is hollowed to accommodate bearings and a return spring. In the U.S. patent to Eckert No. 3,735,302 an armature moves on a guide loft against the force of a spring. Other U.S. patents showing electromagnetic actuators generally of the type herein disclosed and claimed are U.S. Pat. Nos. 3,161,791; 2,407,603; 3,381,250; 1,226,697; 3,225,747; and 2,802,428.
It is an object to provide a novel electromagnetic actuator which is relatively economical to construct while at the same time providing an output essentially linear with respect to the input current.
This and other objects are achieved by the provision of an armature secured to an output shaft so that both are movable linearly. Spaced bearings mounted along the shaft help to ensure linear movement of the output shaft.